The present invention relates to a method for assisting a mobile-unit-dedicated data delivery processing. In particular, it relates to a technology for assisting an enhancement in delivery quality of contents data when the contents data is delivered from a node existing on a wired network to a node existing on a wireless network.
As a communications method for assisting an enhancement (i.e., prevention of data missing) in delivery quality of such data as contents when such data as contents is delivered from a delivery node existing on a wired network to a mobile node existing on a wireless network, there has been known a method disclosed in a published US patent application US2002/0094813A1.
In the method disclosed in this document, plural cache servers are located between the delivery node and the mobile node. Moreover, if one of the cache servers (first cache server) existing on a route between the delivery server and the mobile node holds information that the mobile node requests, this information is delivered not from the delivery server but from the first cache server.
Furthermore, if the mobile node changes its physical existence position and thus the route between the delivery server and the mobile node has changed, the following operation will be performed: First, it is checked whether or not one of cache servers (second cache server) existing on a new route holds the information. If the second cache server holds the information, the second cache server acquires information on the already delivered information from the first cache server. In addition, the second cache server delivers the remaining information to the mobile node.
In this way, as the mobile node changes its physical existence position, another cache server delivers the remaining information portion to the mobile node. This allows proposal of efficient information delivery.